There was the president talking about Wall Street bankers and then one of the dirty rats ran across his path. Or perhaps it was a very big mouse ‑ or even a vole.

Whatever the creature was, dozing White House staff and reporters were shaken from Barack Obama's speech on financial regulation and "fat cat bankers" by the sight of a rodent scurrying in front of his podium before making for the famous Rose Garden bushes.

The president wasn't taking questions from reporters, but there were plenty among members of the crowd. Was this the same rat that appeared a week ago when Obama was speaking about the Gulf coast oil spill?

And there were the jokes about a mole in the White House, a rat in the Rose Garden and, inevitably, the sinking ship that is the Obama administration.

Russell Link, a wildlife biologist, said it was hard to tell exactly what kind of rodent had scuttled across the president's path.

"I would partially rule out rat. That's due to the lack of a tail that is typically equal to a rat's body length," he told the Associated Press. "My suspicion is it's a vole, commonly called a 'meadow mouse' out our way."

Obama survived the encounter better than Jimmy Carter's run-in with a 'killer' swamp rabbit in 1979 when the then president was attacked by the creature while fishing from a boat.

Through it all, Obama never even noticed the rodent, which was probably the creature's good fortune given the startling ease with which he caught a fly in his hand last year.